The Changes And Predictive Value Of Heart Rate Turbulence And Microvolt T Wave Alternans In Patients With Acute Coronary Sydrome

Objective:The objective of this study is to analyse the changes and predictive value of Heart rate turbulence and microvolt T wave alternans based on dynamic electrocardiogram in the patients with acute coronary syndrome,to observe the variation of HRT and MTWA between the two types of ACS,to evaluate the value of all indicators as predictors of MACE,and to find the optimal way to combine and use these techniques in clinical practice。Method:From December 2012 to December 2014,Patients (56 cases) who were diagnosed with ACS were enrolled in the study as the observation group(male 37,female 19. aged 32-84 years old, mean aged 63.8±9.7years old).50 cases received coronary angiography with negative results were selected as the control group (male 32,female 18,aged 40-79 years old, mean aged 60.7±9.1 years old). Analyze all the patients with 24 hours Ambulatory ECG documents and calculate the indicators, the HRT was evaluated by the turbulence onset(TO) and turbulence slope(TS) and the MTWA was evaluated by the maxMTWA. The observation group were further divided into unstable angina pectoris subgroup (UAP,32 cases) and acute myocardial infarction subgroup (AMI,24 cases) according to the syndrome、electrocardiographic and cardiac muscle enzyme. The patients were divided into single vessel subgroup(16 cases), two vessel subgroup(22 cases)and three vessel subgroup(18 eases) according to the degree of coronary artery lesions involvement. The duration of follow-up was 12 months, and the occurrence of MACE was observed.Result:1. Compared the ACS patients with the patients in control group, TO、TS was increased significantly(P<0.01), MTWAmax was increased partly(P<0.05).2. Compared the patients in AMI subgroup with the patients in UAP subgroup, TO、TS was different from the UAP group (P<0.05).3. Compared the patients in Single vessel subgroup with three vessel subgroup: there were significant differences in TO. TS, MTWAmax TS、MTWAmax (p<0.05).4. Using, TO>0, TS<2.5ms/RR as reference criterion, When it was used to predict MAE in patients with ACS, the sensitivity was 64.11% and 53.11% respectively. The specificity was 76.33% and 87.62%. The positive predictive value was 73.84% and 83.84%. The negative predictive value was 83.70% and 93.46%.The areas under the ROC curves were 0.514,0.691 respectively standing for TO, TS.5. Using MTWAmax>47 μV as reference criterion, When it was used to predict MAE in patients with ACS, the sensitivity was 56.67% The specificity was 67.62%. The positive predictive value was29.02%. The negative predictive value was 92.20%.The areas under the ROC curves were 0.712.6. Combining HRT and MTWAmax as reference criterion, When it was used to predict MAE in patients with ACS, the sensitivity was 35.61%, the specificity was 97.42%,the positive predictive value was 62.25%,and the negative predictive value was 92.39%.The area under the ROC curves was 0.769.ConclusionThe non-invasive cardiac electrical indicators(HRT、MTWA) of the patients with ACS have been abnormal in different degrees. It demonstrated that the autonomic nervous system function was impaired obviously and because of myocardial ischemia ornecrosis.TO,TS and MTWAmax could be used to predict the prognosis of the patients with ACS and identify high risk ones from them. United TO、TS and MTWAmax can improve the predictive capability.